Publications (4)12.36 Total impact
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Article: New betulinic acid derivatives induce potent and selective antiproliferative activity through cell cycle arrest at the S phase and caspase dependent apoptosis in human cancer cells.
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ABSTRACT: New semisynthetic derivatives of betulinic acid (BA) RS01, RS02 and RS03 with 18-45 times improved cytotoxic activity against HepG2 cells, were tested for their ability to induce apoptosis and cell cycle arrest in HepG2, HeLa and Jurkat cells. All the compounds induced significant increase in the population at the S phase more effectively than BA. RS01, RS02 and RS03 were also found to be potent inducers of apoptosis with RS01 being markedly more potent than BA, suggesting that the introduction of the imidazolyl moiety is crucial for enhancing the induction of apoptosis and the cell cycle arrest. The mechanism of apoptosis induction has been studied in HepG2 cells and found to be mediated by activation of the postmitochondrial caspases-9 and -3 cascade and possibly by mitochondrial amplification loop involving caspase-8. These facts were corroborated by detection of mitochondrial cytochrome c release and DNA fragmentation. Because RS01, RS02 and RS03 exhibited significant improved antitumor activity with respect to BA, they may be promising new agents for the treatment of cancer. In particular, RS01 is the most promising compound with an IC(50) value 45 times lower than BA on HepG2 cells and 61 times lower than the one found for the non-tumoral Chang liver cells.Biochimie 03/2011; 93(6):1065-75. · 3.02 Impact Factor -
Article: Synthesis and structure-activity relationship study of novel cytotoxic carbamate and N-acylheterocyclic bearing derivatives of betulin and betulinic acid.
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ABSTRACT: Chemical transformation studies were conducted on betulin and betulinic acid, common plant-derived lupane-type triterpenes. The concise synthesis, via a stepwise approach, of betulin and betulinic acid carbamate and N-acylheterocyclic containing derivatives is described. All new compounds, as well as betulinic acid were tested in vitro for their cytotoxic activity. Most of the compounds have shown a better cytotoxic profile than betulinic acid, including the synthesized betulin derivatives. Compounds 25 and 32 were the most promising derivatives, being up to 12-fold more potent than betulinic acid against human PC-3 cell lines (IC(50) values of 1.1 and 1.8 microM, respectively).Bioorganic & medicinal chemistry 06/2010; 18(12):4385-96. · 2.82 Impact Factor -
Article: Novel semisynthetic derivatives of betulin and betulinic acid with cytotoxic activity.
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ABSTRACT: A series of new imidazole carboxylic esters (carbamates) and N-acylimidazole derivatives of betulin and betulinic acid (14-29) have been synthesized. The new compounds were screened for in vitro cytotoxicity activity against human cancer cell lines HepG2, Jurkat and HeLa. A number of compounds have shown IC(50) values lower than 2 microM against the cancer cell lines tested and the vast majority has shown a better cytotoxicity profile than betulinic acid, including the betulin derivatives. N-Acylimidazole derivatives 26 and 27 (IC(50) 0.8 and 1.7 microM in HepG2 cells) and the C-3 carbamate derivative 16 (IC(50) 2.0 microM in HepG2 cells) were the most promising compounds. Based on the observed cytotoxicity, structure-activity relationships have been established.Bioorganic & medicinal chemistry 08/2009; 17(17):6241-50. · 2.82 Impact Factor -
Article: Bismuth triflate-catalyzed Wagner-Meerwein rearrangement in terpenes. Application to the synthesis of the 18alpha-oleanane core and A-neo-18alpha-oleanene compounds from lupanes.
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ABSTRACT: The use of bismuth(III) salts as catalysts for the Wagner-Meerwein rearrangement of lupane derivatives with expansion of ring E and formation of an additional O-containing ring is reported. This process has also been extended to other terpenes, such as the sesquiterpene (-)-caryophyllene oxide. When the reaction was performed with oleanonic acid, 28,13beta-lactonization occurred, without Wagner-Meerwein rearrangement. Under more vigorous reaction conditions, dehydration of the 3beta-hydroxyl group and subsequent additional Wagner-Meerwein rearrangement led to the selective synthesis of A-neo-18alpha-oleanene compounds, in very high yields.Organic & Biomolecular Chemistry 03/2009; 7(3):508-17. · 3.70 Impact Factor
